The “Raging Bull” himself got a little choked up during an interview about his film “Silver Linings Playbook” with Katie Couric.

The “Katie” host asked Robert De Niro if he felt a larger share of responsibility doing a project that director David O. Russell was “personally invested in.”

“Of course, I understand,” replied De Niro. After a long pause, he tried to continue, but then the usually tough-guy actor welled up.

He continued, “I don’t like to get emotional, but I know exactly what he goes through.”

De Niro’s unusually strong reaction perhaps hit close to home. De Niro’s dad, Robert (same name), was believed to be bipolar and suffered from bouts of paralyzing depression. The actor’s dad Robert Henry De Niro was an abstract expressionist painter who died in 1993 at age 71.

Russell’s film – and Bradley Cooper’s bipolar character Pat – was inspired by Russell’s son who suffers from a mood disorder.

Russell said in the interview, “I’ve had a son who has a mood disorder, which means someone that can have moods that can pull them down the drain and send the home to a tornado in moments.”

The Oscar-nominated director recalled speaking with De Niro about the “Silver Linings” screenplay in his apartment, where the veteran performer connected to the material very emotionally.

“I thought he was having hay fever, then I realized he was having an emotional reaction and I sat there and watched Robert De Niro cry for 10 minutes and I said, ‘Wow he’s really connecting with this material and this would be [a] beautiful thing if it could work out, because I think his heart would be there’ and it is there.”